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|\J^A SouJtKcJVv. RIVER ITCHEN CATCHMENT MANAGEMENT PLAN FINAL REPORT NRA National Rivers Authority Southern Region MISSION STATEMENT The NRA’s mission is : "We will protect and improve the water environment by the effective management of water resources and by substantial reductions in pollution. We will aim to provide effective defence for people and property against flooding from rivers and the sea. In discharging our duties we will operate openly and balance the interests of all who benefit from and use rivers, groundwaters, estuaries, and coastal waters. We will be businesslike, efficient and caring towards our employees". Our Aims are to : Achieve a continuing overall improvement in the quality of rivers, estuaries and coastal waters, through the control of pollution. Manage water resources to achieve the right balance between the needs of the environment and those of the abstractors. Provide effective defence for people and property against flooding from rivers and the sea. Provide adequate arrangements for flood forecasting and warning. Maintain, improve and develop fisheries. Develop the amenity and recreation potential of inland and coastal waters and associated lands. Conserve and enhance wildlife, landscape and archaeological features associated with inland and coastal waters of England and Wales. Improve and maintain inland waters and their facilities for use by the public where the NRA is the navigation authority. Ensure that dischargers pay the costs of the consequences of their discharges, and, as far as possible, to recover the costs of environment improvements from those who benefit. Improve public understanding of the water environment and the NRA's work. Improve efficiency in the exercise of the NRA's functions and to provide challenge and opportunity for employees and show concern for their welfare. NRA Copyright waiver This document is intended to be used widely and may be quoted, < any way, provided that extracts are not quoted out of context and is given to the National Rivers Authority. E n v ir o n m e n t Ag e n c y © Crown Copyright The plans in this document are based on the Ordnance Survey and s NATIONAL LIBRARY & permission of the Controller of Her Majesty’s Stationery Office. INFORMATION SERVICE SOUTHERN REGION Published December 1993 Guildbourne House, Chatsworth Road. Worthing, West Sussex BN 11 1LD River Itchen Catchment Management Plan RIVER ITCHEN CATCHMENT MANAGEMENT PLAN FINAL PLAN CONTENTS INTRODUCTION 3 SECTION A : STATE OF THE CATCHMENT A.1 SUMMARY 4 A.2 HYDROLOGY AND RAINFALL 5 A.3 PUBLIC WATER SUPPLY 6 A.4 WATER SUPPLY FOR INDUSTRY AND AGRICULTURE 7 US USE OF THE WATER RESOURCE 7 A.6 WATER QUALITY 8 A.7 EFFLUENT DISPOSAL 9 A.8 INTERMITTENT AND DIFFUSE POLLUTION 9 A.9 FLOOD DEFENCE AND LAND DRAINAGE 10 A.10 LANDSCAPE AND CONSERVATION 11 A.11 FISHERIES 12 A.12 RECREATION AND AMENITY 13 A.13 INTERACTION WITH PLANNING AUTHORITIES 14 SECTION B : KEY ISSUES AND MANAGEMENT PROPOSALS 15 SECTION C : ACTION PROGRAMME 21 • APPENDICES • APPENDIX 1 SUMMARY OF CATCHMENT STATISTICS 25 APPENDIX 2 NWC RIVER CLASSIFICATION SYSTEM 29 APPENDIX 3 GLOSSARY OF TERMS AND UNITS 31 APPENDIX 4 FURTHER READING 37 ENVIRONMENT AGENCY Page 1 River Itchen Catchment Management Plan ( ■ ■ River Itchen Catchment Management Plan INTRODUCTION The function of Catchment Management Plans is to promote the overall vision of The National Rivers Authority for the catchment in question. They are central to the development of NRA policy, assigning priorities for its own activities, providing a framework for decisions where the Authority has powers of control and guiding others towards the sustainable use of the resources of the catchment. This Final Plan represents the second phase of planning for the Itchen Catchment, drawing together information and comment from the earlier consultation stage. Sufficient descriptive text is included to support the Key Issues and Management Proposals, but the reader is referred to the earlier Itchen Catchment Consultation Report for more detailed information. Recommendations have been framed in the context of a ten year planning horizon but will be reviewed at intervals in the light of changing circumstances. The NRA is consulted regularly on planning matters falling within its terms of reference, both in the preparation of statutory Plans and in connection with individual applications for planning consent. Recent guidance from the Department of the Environment has strengthened the links between the N RA and the Planning Authorities, but ultimate planning control remains with them. Catchment Management Plans are complementary to the statutory Plans of Local Authorities; by stating clearly the NRA vision it is hoped they will make a positive input to the formal planning process, which is the responsibility of the District and County Councils. IT IS IMPORTANT THAT THIS CATCHMENT PLAN IS READ IN THE CONTEXT OF COUNTY AND DISTRICT PLANNING POLICIES, ESPECIALLY THOSE CONCERNED WITH RECREATION, CONSERVATION, WASTE DISPOSAL, MINERAL EXTRACTION AND COUNTRYSIDE MANAGEMENT. Page 3 River Itchen Catchment Management Flan A.1 SUMMARY This Management Plan covers the catchment of the River Itchen and its estuary upstream of Dockhead, as shown on the accompanying map. The population of the catchment is approximately 240,000, the main towns being Southampton, Eastleigh and Winchester. Upstream of Eastleigh the catchment is rural with a combination of arable and livestock farming, whilst downstream the area is largely urban and includes heavy industry. The River Itchen rises on the Upper Chalk of the Hampshire Downs as three spring fed tributaries; the Candover Stream, the River Aire and the Cheriton Stream (or Tichbourne) which join just west of New Alresford. From here the river flows west to Winchester and then southwards, through the outskirts of Eastleigh and Southampton to the tidal limit at Woodmill. Monks Brook, which drains a largely urban catchment, joins the estuary just downstream of the tidal limit. For much of its length the River Itchen is divided between two or more separate channels running parallel to each other, with many structures to regulate flows and levels. This situation arises from past uses of the river to provide water power for milling, to supply water meadows, and from the development of navigation. Between Winchester and Eastleigh the former Itchen Navigation flows parallel to or coincident with the river. W hilst dating from the reign of Charles II, the navigation fell into disuse many years ago. There is no public right of navigation above the tidal limit. The character of the River Itchen owes much to its geology: where the Chalk is exposed in the upper catchment most of the rainfall soaks directly into the ground and there are few tributaries; below Eastleigh the river flows over younger sands, silts and clays which are less permeable than the Chalk, allowing the development of surface streams such as the Monks Brook. The Chalk valleys of the Downs were formed in the Ice Age when the ground was frozen, but now that the Chalk is permeable to water many valleys are dry, or support winterbournes. The Chalk provides the river with a stable flow of cool, clear, hard, alkaline spring water, giving an ideal environment for the fisheries which make the Itchen one of the most famous of trout streams. There is a thriving cress industry in the Alresford area, supplied by artesian springs and boreholes. Fish farming is also an important industry with four major farms in the upper catchment. The Chalk aquifer is exploited for water supply by major abstractions between King’s Worthy and Otterboume. There are also two significant abstractions for public water supply direct from the river at Otterbourne and Gaters Mill. Flood defence is not an important issue along the main River Itchen, although there were formerly problems on tributaries draining urban areas such as Chandlers Ford and Eastleigh. Low-lying water meadows flood regularly in winter, to the benefit of their wildlife. When necessary, low river flows are supported by pumping groundwater from the upper catchment (the Candover and Aire Schemes) to maintain water quality in the lower reaches and to ensure that public water supplies can be maintained without damaging environmental interests. TO BASINGSTOKE EAST OAKLEY NRA N t o P O 3 C 0 /' A ANDOVER MICHELDEyER SUTTON SCOTNEY FOUR MARKS TO :iNG'S £ / OLD STOCKBRIDGE ^ S WORTHYy y ITCHEN | ALRESFORD .ET(pN / • ABBAS / r SPARSHOLT a ) NEW ^fy\LRESFORD W ir^HESTER'^p3fc|i^3I iTWYFORD CHANDLERS JSHAWFORfe FORD JRAMBRIDGE' Tt r - MEON <5? EAST }WvP^u MEON NORTH BADDESLEY 'M27 FAIR LEGEND OAK COAST LINE INGTON RIVER ITCHEN TOPOGRAPHIC CATCHMENT LANE f ? STREAM RIVER ITCHEN SHOUNG 'COMMON STREAM TOWNS ^ TO FAREHAM MAJOR ROADS SOUTHAMPTON 0 1 2 3 4 5 10 km THE CATCHMENT =l 1 0 0 0 ^ NRA 800 _ MEAN__ RAINFALL KEY 600 _ JQTAL RAINFALL 4 0 0 - MEAN EFFECTIVE 200 _ RAINFALL [0] EFFECT RAINFALL 1987 1988 1989 1990 1991 Rainfall Record from Otterboume Station Actual Evaporation Data from MORECS Database DAILY FLOW HYDROGRAPH (m 3s _1) M ax. and min. daily mean flows from 1958 to 1990 with an example yearly hydroGraph (1990) 100.0 0 . J__ I__ l__ L J__ I__ I__ L - 100.00 50.00 J _ 50.00 10.00_ i_ 10.00 5 .0 0 - 5.00 1.00. 1.00 HIGHBRIDGE AND ALLBROOK Site name : LOWER WIELD FARM National Grid reference : SU 6360 4049 Well number : SU64/28 Aquifer : CHALK AND UPPER GREENSAND MeasurinG level : 158.95 100 o 98 E _i 96 < —33 < 1987 1988 1989 1990 1991 Max, Min and Mean values calculated from years 1958 to 1989 HYDRQMETRIC DATA r River Itchen Catchment Management Plan K 2 HYDROLOGY AND RAINFALL The upstream Chalk groundwater catchment is approximately 130km2 larger than the surface water catchment, extending eastwards beneath the topographic catchment of the River Wey on the far side of the Hampshire Downs ridge.

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